In 2010, Maricopa County Sheriff's deputies, left, check the shoes of a suspect arrested during a crime suppression sweep in Phoenix. A judge in Arizona on Sept. 18, 2012 ruled that police can immediately start enforcing the most contentious section of the state's immigration law, the so-called "show me your papers" provision.

Phoenix — An education campaign for illegal immigrants to remain largely silent when they're pulled over by police is being put into practice in Arizona after a federal judge ruled that the most contentious part of the state's immigration law can take effect.

Natally Cruz and Leticia Ramirez have been telling immigrants who are in the United States illegally, like themselves, that they should offer only their name and date of birth — and carry no documents that show where they were born.

U.S. District Judge Susan Bolton ruled Tuesday that police can immediately start enforcing the law's so-called "show me your papers" provision. It requires officers, while enforcing other laws, to question the immigration status of those suspected of being in the country illegally.

Ramirez and Cruz had remained hopeful the provision would be blocked, but they were preparing by sending a message to communities of illegal immigrants that they should respectfully stand their ground against police.

"We want to teach the community how to defend themselves, how to answer to police, how to be prepared, and to have confidence that they're going to have help," Ramirez said.

Bolton's decision is the latest milestone in a two-year legal battle over the requirement.

The U.S. Supreme Court upheld the provision in June on the grounds that it doesn't conflict with federal law. Opponents responded by asking Bolton to block the requirement on different grounds, arguing its enforcement would lead to systematic racial profiling and unreasonably long detentions of Latinos. Bolton said early this month she wouldn't block the provision.

A coalition of civil rights groups is awaiting a ruling from the 9th U.S. Circuit Court of Appeals on their latest effort to prevent the questioning requirement from taking effect.

A hotline operated by civil rights advocates recently has been fielding calls from people wanting to know what their rights are if officers question their immigration status.

Lydia Guzman, leader of the civil rights group Respect-Respeto, said additional volunteers are being sought to answer calls and document reports of abuses. If a police agency plans a special immigration patrol, volunteers armed with video cameras will be sent there to capture footage of traffic stops, Guzman said.

Arizona lawmakers passed the law in 2010 amid voter frustration with the state's role as the busiest illegal entry point in the country. Five states — Alabama, Georgia, Indiana, South Carolina and Utah — have adopted variations on Arizona's law.

It's a tool for local police, but it won't cure the state's immigration woes, said Republican Gov. Jan Brewer, who signed the measure.

"Only the federal government has the resources and responsibility necessary to achieve that," Brewer said.

The law's opponents are spreading out across the state, asking police departments not to enforce the provision. The incentive they offer: better cooperation from immigrants who would be more likely to report crimes, said Carlos Garcia, an organizer with immigrant rights group the Puente Movement.

Not enforcing the provision could open up officers to lawsuits from people claiming the agencies aren't fully enforcing the law.

Federal officials say they will check people's immigration status when officers call. But they'll send an agent to arrest someone only when it fits with their priorities, such as catching repeat violators and those who are a threat to public safety and national security.

Cruz, originally from Guanajuato, Mexico, said she has never been pulled over in the United States but fears the law will lead to racial profiling and will separate families.

Bolton initially blocked the provision after the Obama administration challenged it on the grounds that federal immigration law trumps state law. She has said opponents are speculating on racial profiling claims.

Ramirez said she isn't willing to give up 18 years in the United States over a law she sees as a threat to her livelihood.

Her father brought their family to the U.S. from Torreon in the Mexican state of Coahuila because he couldn't find work there and wanted a better future for them.

She's been a visible part of the legal battle because she sees importance in her education mission, particularly for those who don't get involved in immigrant-rights groups or don't watch television to keep up-to-date on the law.

"That's what I'm afraid of — that a lot of the people don't know what to do," Ramirez said.